HONG KONG (Reuters) - Ever wondered how we are able to
conduct a conversation at a noisy party?

Researchers from Japan, Canada and Germany have found that
it is our left brain that picks out the desired sounds from a
cacophony of loud, competing sounds.

"In daily life, we are always exposed to several noises at
the same time and we have to pick up important signals, for
example, speech sounds, from the background noises," wrote
researcher Ryusuke Kakigi from Japan's National Institute for
Physiological Sciences.

"We found that the left hemisphere is generally dominant
for auditory processing in noisy environments," he wrote in an
email response to questions from Reuters.

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It is well known that speech signals are processed in the
left brain.

But this study, led by Hidehiko Okamoto and Christo Pantev
at the University of Muenster in Germany, furthers our
understanding of how the human brain is able to zero in on the
specific sounds it wants and process them.

In the latest issue of the online journal BMC Biology, the
scientists said they used neuroimaging and observed neural
mechanisms in volunteers who were exposed to different
combinations of tests and background sounds.

"Test sounds were played either to the left or to the right
ear, while the competing noise was presented either to the same
or to the opposite ear," they wrote.

"By monitoring the brain's response to these different
sound combinations, the team observed that the left hemisphere
was the site of most neural activity associated with processing
sounds in a noisy environment."